diff --git a/x-pack/platform/plugins/shared/actions/server/integration_tests/__snapshots__/connector_types.test.ts.snap b/x-pack/platform/plugins/shared/actions/server/integration_tests/__snapshots__/connector_types.test.ts.snap
index e876d601bf7cb..c4e3e77eab4f1 100644
--- a/x-pack/platform/plugins/shared/actions/server/integration_tests/__snapshots__/connector_types.test.ts.snap
+++ b/x-pack/platform/plugins/shared/actions/server/integration_tests/__snapshots__/connector_types.test.ts.snap
@@ -10706,6 +10706,27 @@ Object {
             ],
             "type": "number",
           },
+          "defaultModel": Object {
+            "flags": Object {
+              "default": [Function],
+              "error": [Function],
+              "presence": "optional",
+            },
+            "metas": Array [
+              Object {
+                "x-oas-optional": true,
+              },
+            ],
+            "rules": Array [
+              Object {
+                "args": Object {
+                  "method": [Function],
+                },
+                "name": "custom",
+              },
+            ],
+            "type": "string",
+          },
           "headers": Object {
             "flags": Object {
               "default": [Function],
diff --git a/x-pack/platform/plugins/shared/stack_connectors/common/openai/schema.ts b/x-pack/platform/plugins/shared/stack_connectors/common/openai/schema.ts
index db64b1f10ad2b..e54c09c66aa15 100644
--- a/x-pack/platform/plugins/shared/stack_connectors/common/openai/schema.ts
+++ b/x-pack/platform/plugins/shared/stack_connectors/common/openai/schema.ts
@@ -20,6 +20,7 @@ export const ConfigSchema = schema.oneOf([
     apiUrl: schema.string(),
     headers: schema.maybe(schema.recordOf(schema.string(), schema.string())),
     contextWindowLength: schema.maybe(schema.number({})),
+    defaultModel: schema.maybe(schema.string()),
   }),
   schema.object({
     apiProvider: schema.oneOf([schema.literal(OpenAiProviderType.OpenAi)]),
diff --git a/x-pack/platform/plugins/shared/stack_connectors/server/connector_types/openai/openai.ts b/x-pack/platform/plugins/shared/stack_connectors/server/connector_types/openai/openai.ts
index 6f3abebc57eef..af6602f28b280 100644
--- a/x-pack/platform/plugins/shared/stack_connectors/server/connector_types/openai/openai.ts
+++ b/x-pack/platform/plugins/shared/stack_connectors/server/connector_types/openai/openai.ts
@@ -424,7 +424,9 @@ export class OpenAIConnector extends SubActionConnector<Config, Secrets> {
         messages,
         model:
           rest.model ??
-          ('defaultModel' in this.config ? this.config.defaultModel : DEFAULT_OPENAI_MODEL),
+          ('defaultModel' in this.config
+            ? this.config.defaultModel ?? DEFAULT_OPENAI_MODEL
+            : DEFAULT_OPENAI_MODEL),
       };
 
       connectorUsageCollector.addRequestBodyBytes(undefined, requestBody);